Means for piercing and stripping thick material

ABSTRACT

Means for piercing and stripping various kinds of material, comprising, a punch retaining means, a punch for piercing the material, means securing the punch to the punch retaining means, and a resiliently yieldable stripping means operatively connected with the punch to strip the pierced material from the punch and connected with the punch so that forces imposed on the punch when the punch pierces through the material are absorbed by the stripping means, and so that the stripping means reacts between the punch and the pierced material to strip the material from the punch and the stripping force is thus transferred via the stripping means directly to the punch to protect the means securing the punch to the punch retaining means.

i United States Patent Whistler, Jr. et al.

MEANS FOR PIERCING AND STRIPPING THICK MATERIAL Inventors: Lawrence V.Whistler, Jr., 251

Doncaster Rd.; Lawrence V. Whistler, III, 368 Argonne Dr., both ofKenmore, NY. 14217; .Harold J. Whistler, 22 Highland Dr., Williamsville,NY. 14221 Filed: Apr. 13, 1973 Appl. No.: 350,789

US. Cl. 83/139, 83/140 Int. Cl B2ld 45/00, B26f 1/02 Field of Search83/139, 138, 140; 279/30 References Cited UNITED STATES PATENTS PrimaryExaininer-Donald R. Schran Attorney, Agent, or FirmShoemaker and MattareABSTRACT Means for piercing and stripping various kinds of material,comprising, a punch retaining means, a punch for piercing the material,means securing the punch to the punch retaining means, and a resilientlyyieldable stripping means operatively connected with the punch to stripthe pierced material from the punch and connected with the punch so thatforces imposed on the punch when the punch pierces through the materialare absorbed by the stripping means, and so that the stripping meansreacts between the punch and the pierced material to strip the materialfrom the punch and the stripping force is thus transferred via thestripping means directly to the punch to protectthe means securing thepunch to the punch retaining means.

9 Claims, 10 Drawing Figures PATENTEDHAR I 81915 SHEET 1 0F 2PATENTEDHARWQYS 3,871,254

SHEET 2 0F 2 FIG. 7.

MEANS FOR PIERCING AND STRIPPING THICK MATERIAL BACKGROUND OF THEINVENTION In conventional piercing and stripping means, when relativelyheavy gauge stock or material is punched or pierced, failure of themeans holding the punch to the punch retaining means is frequentlyexperienced, since as the punch is pushed through the material, itreaches a point where the punch bursts" through the material,and'thesudde'n release of the punch pressure results in substantially anexplosion type effect or load on the punch. Further, in conventionalpunch means, the stripper for stripping the pierced material from thepunch is engaged between the punch retaining means and the piercedmaterial; and accordingly, there is a tendency for the stripper to pullthe punch from the punch retaining means when the pierced material isstripped from the punch.

In the present invention, the stripping means is engaged between theworkpiece or material to be pierced and a head or shoulder means on thepunch, so that as the punch passes through the workpiece, the shock loadresulting from the bursting or explosive effect obtained as the punchbreaks through the workpiece is absorbed by the stripping means and isnot transmitted to the means retaining the punch to the punch shoe orpunch retainer. Further, when the stripping means strips the piercedworkpiece from the punch, the stripping force is transferred completelyto the punch and not to the punch retaining means; and accordingly,there is no tendency for the stripper to pull the punch from the punchretaining means as in conventional devices. I

According to the invention, the stripper means may comprise an elastomermaterial such as rubber or polyurethane or the like, or a spring means,but it has been found that polyurethane works exceptionally well and issuperior to rubber or the like.

OBJECT OF THE INVENTION It is an object of the invention to .provide apunch means and stripping means for piercing heavy gauge stock ormaterial wherein the stripper means is engaged I against a shoulder onthe punch itself and against the stock or material so that as the punchbursts" through the workpiece, the explosive force which results isabsorbed by the stripper means, and the force exerted in stripping thepierced workpiece from the punch is transmitted to the punch itself andnot the punch retaining means, to thus protect the means securing thepunch to the punch retaining means.

BRIEF DESCRIPTION OF THE DRAWINGS 'FIG. 1 is a sectional view inelevation of a first form of the invention shown in position immediatelyprior to engagement with a workpiece.

FIG. 2 is a view similar to FIG. 1 showing the punch pushed through theworkpiece and with the stripper means in compressed condition.

FIG. 3 is a view in section taken along line 33 of FIG. 2.

FIG. 4 is an exploded perspective view of the punch and stripper meansof the present invention.

. the punch.

FIG. 7 is a view similar to FIG. 6 with the punch pushed through theworkpiece. v

FIG. 8 is a' view in section taken along line 8-8 in FIG. 6, and

FIG. 9 is a plan view of the snap ring against which the stripper meansof FIGS. 6 and 7 abuts.

DETAILED DESCRIPTION OF THE INVENTION In the drawings, wherein likereference numerals indicate like parts throughout the several views, apunch and stripper means according to the invention are indicatedgenerally at 10 and comprise a punch shoe 11 to which a punch retainer12 is suitably'secured in a conventional manner. The punch retainer hasa socket 13 therein defining an axially, downwardly presented shoulderor surface 14. An elongate solid punch 15 having a body portion 16, adiametrically enlarged head portion 17 and a reduced diameter, elongatedpiercing point or punch point 18 thereon is secured to the punchretainer at the head 17 thereof with the head received in the recess 13and against the surface 14. The punch is secured in the recess by meansof a set screw or plurality of set screws 19 extended at an anglethrough the punch retainer and into engagement with the outer surface ofthe head portion 17 of the punch 15. A shallow, concave annular groove20 is in the punch between the body portion 16 and head portion 17thereof and defines an annular, axially downwardly presented shoulder20'. An elongate, cylindrical, elas tomer stripper 21 of a suitablematerial such as rubber, polyurethane, or thelike, is fitted over thebody portion 16 and in its normal, expanded condition, extends thelength of the body portion 16 and punch point 18. The stripper 21 has alower annular cap 22 of a suitable rigid material such as fiber or steelor the like, the cap 22 having an annular upstanding rim or flange 23thereon with a radially inwardly directed rib or lip 24 engaged againstthe lower outer surface of the stripper 21 to maintain the cap 22 inposition. A similar cap or cap means 25 is similarly secured to theupper end of stripper 21 and the stripper is secured to the punch bymeans of a set screw or plurality of set screws 26 extended radiallythrough the upper cap 25 into engagement with the annular groove 20 inthe punch. The upper inner marginal portion of upper cap 25 is engagedagainst the shoulder 20' on the underside of head 17 on the punch 15.

A workpiece W is supported immediately beneath the punch and stripper ina conventional manner and on top of a die bushing 27 which is held to adie retainer (not shown) in a conventional manner, the die retainer inturn being supported on a die shoe (not shown) in a conventional manner.

As seen in FIG. 2, the punch 15 has been pushed through the workpiece,and a slug S of the workpiece is separated from the workpiece and isfalling away I therefrom. The sudden release of the load on the punch asthe punch breaks or bursts through the workpiece and the explosiveeffect thus produced are absorbed by the stripper, which is incompressed condition at this stage of operation and acts in the natureof a shock absorber. Thus, the set screws 19 which retain the punch 15to the punch retainer 12 are protected; and they are not sheared asfrequently occurs in conventional punch and stripper means when a heavyworkpiece is pierced, and wherein the stripping load is imposed on thelower face of the punch retainer;

Thus, with the arrangement according to the invention, all of the forceresulting from the punch breaking through the workpiece W, and fromstripping the pierced workpiece from the punch, is transferred throughthe stripper to the shoulder and thus directly to the punch and not tothe punch retaining means as occurs in conventional devices.

In FIGS. 5 and 5a, a slightly modified form of the invention isillustrated, wherein rather than the set screws 19, a ball lockmechanism 28 is utilized to secure the punch in position relative to thepunch retainer 12. The ball lock 28 includes an inclined cavity or bore29 in the punch retaining means 12 in which is fitted a ball 30 and coilspring 31 for urging the ball downwardly in the bore 29. Ashallowdepression of substantially tear drop shape 32 is in the outerside surface of the head 17 of punch 15' and the ball 30 is engaged inthis depression 32 to securely lock the punch in retainer 12. The upperend of the head 17 of the punch 15' is engaged against a back up platesupported on the punch shoe in a conventional manner. In all otherrespects this form of the invention is identical to the form of theinvention illustrated and described with reference to FIGS. 1 through 4.

In FIGS. 6 through 9, a further modified punch and stripper means 10"comprises an elongate solid punch 34 having a body portion 16' and areduced diameter punch end or piercing point 18 and an annular channelor groove 35 adjacent an upper end portion of the body portion 16'. Anannular channel or groove 36 is in the punch at the upper end of thebody portion and defines an axially, downwardly facing shoulder 37. Thepunch 34 has a head portion 38 of substantially the same diameter as thebody portion 16', with the head 38 secured in punch retainer 12 by meansof a ball lock 30, 3l, 32 as in the previously described embodiment, andwith the upper end of the head 38 engaged against the underside of theback up plate 33 suitably secured to the punch shoe 11.

A snap ring 39 is fitted within the channel 36 between the body portion16 and head 38 of punch 34, in spaced relation to the punch retainingmeans 12, and a modified stripper means 40 is operatively connected withthe punch 34 and is engaged against the underside of snap ring 39. Themodified stripper means 40 includes an annular collar or cap means 41secured to the upper end portion of the body portion 16 by means-of aplurality of radially extending set screws 19 extended through thecollar 41 and into the groove 35 in the body portion 16 of the punch 34.

A plurality of spaced apart bores 42 extend from the upper surface ofthe collar 41 toward the lower surface thereof and a plurality of guidepins 43 are slidably positioned in the bores 42, and each has anenlarged head 44 thereon which engages against the bottom of the bore 42of collar 41. The guide pins 43 have threaded lower ends 45 threadablyengaged in spaced apart threaded bores in a'workpiece engaging annularplate or collar 46. A coil spring 47 surrounds each guide pin 43 and isengaged at its lower end with the upper surface of the plate 46 and isengaged at its upper end with the undersurface of collar 41 forurgingthe plate 4 downwardly relative to the punch 34.

The workpiece W is supported in a conventional manner on top of a diebushing 27 which is in turn supported in a die retainer 48 which issuitably supported in a conventional manner on a die shoe 49.

As seen in FIG. 6, the punch is shown in position about to engage theworkpiece W with the springs 47 in expanded condition and the plate orcollar 46 engaged with the workpiece.

In FIG. 7, the punch point 18 has pierced the workpiece W and a slug Sof the workpiece W is removed therefrom. The springs 47 are incompressed condition with the enlarged head 44 of the guide pins 43positioned adjacent the upper end of the bores 42 in collar 41. All ofthe load transmitted from plate 46 to the springs 47 is transmittedthrough the collar 41 to the snap ring 39 and shoulder 37 on the punch34 to thus protect the ball lock 30, 3'1, 32. Accordingly, as the punchis pushed downwardly through the workpiece and as it bursts through theworkpiece with the explosive effect aforedescribed, the entire shockload is absorbed by the springs 47; and as the punch is withdrawn fromthe workpiece, the stripper 40 acts between the snap ring 39 andshoulder 37 and the workpiece W to strip the workpiece W from the punch.

As seen in FIG. 9, the snap ring 39 has a radially extending channel oropen portion 50 therein through which a suitable tool may be inserted todisengage ball 30 from depression 32 to release the punch from the punchretainer 12.

Accordingly, with the present invention, holes have been punched throughinch thick steel, and a /8 inch diameter hole has been punched through a1 inch thick piece of mild steel without danger of damaging or shearingthe means, such as set screws orother suitable means, which hold thepunch to the punch retainer. With conventional devices, the meanssecuring the punch to the punch retainer would likely be damaged ordestroyed if a piece of material of this size were punched or pierced,particularly where punches are utilized which are removably mounted tothe punch retainer. 7

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof, the presentembodiment is therefore illustrative and not restrictive, since thescope of the invention is defined by the appended claims rather than bythe description preceding them, and all changes that fall within themetes and bounds of the claims or that form their functional as well asconjointly cooperative equivalents, are therefore intended to beembraced by those claims.

What is claimed is:

l. A punch for punching holes in material, comprismg:

punch retaining means,

a punch having a head end and a piercing end,

punch securing means engaged with the head end of the punch securing thepunch to the punch retaining means,

axially downwardly facing shoulder means on the punch adjacent the headend thereof axially spaced from the punch retaining means, and

resiliently yieldable stripper means disposed in substantially coaxialrelation with the punch, said stripper means including a cap meanssecured to the punch in coaxial relation therewith in engagement withsaid shoulder means and axially spaced from the punch retaining means,saidv yieldable stripper means engaged at one end against said cap meansand having its other end substantially coplanar with the piercing end ofthe punch, so that when said punch is forced through a piece of materialto pierce the material the stripper means engages between the piece ofmaterial and the cap means and thus acts as a shock absorber absorbingforces resulting from piercing the piece of material and effectingstripping of the pierced piece of material from the punch, withstripping loads imposed on the stripper means transmitted to theshoulder means on said punch to thus protect the punch securing meanssupporting said punch in said punch retaining means.

2. A punch for punching holes in material, comprising:

a punch retainer,

a punch secured at one end thereof to the punch retainer and havingaxially downwardly facing shoulder means thereon spaced from the punchretainer,

punch securing means engaged with said one end of said punch securingsaid punch to the punch retainer,

resiliently yieldable stripper means disposed in substantially coaxiallysurrounding relation to the punch, and

a cap means secured on the punch in engagement with said shoulder meansin axially spaced relation to the punch retainer, said stripper meansengaged at one end thereof against said cap. means and extended at itsother end into substantially coplanar relation with the other end of thepunch, so that when a sheet of material is pierced with the punch andthe punch bursts through the material, the resulting force imposed onthe stripper means is transmitted to the shoulder means on the punchitself, thus protecting the punch securing means from said force.

3. A punch as in claim 2, wherein the stripper means comprises anelastomeric cylindrical stripper fitted over the punch and secured atits upper end to the punch adjacent the upper end of the punch.

4. A punch as in claim 3, wherein said elastomeric stripper is elongateand has a central bore therethrough of substantially the same diameteras the diameter of at least a portion of said punch, said cap meansincluding a hard rigid annular cap secured to each end of saidelastomeric stripper, one of said caps having a plurality of radiallyextending openings therethrough, and set screw means extended throughsaid openings and into engagement with said punch to secure saidstripper to said punch, the other of said caps engageable with aworkpiece to be pierced by said punch.

'5. A punch as in claim 4, wherein said punch is an elongate, solid,cylindrically shaped member having a body portion of the same diameteras the internal bore through the stripper, a reduced diameter punchpoint, and a diameterically enlarged punch head received in and securedto said punch retainer means, and an annular, concave groove in saidpunch between said head and body portion defining with saidhead saidaxially downwardly facing shoulder against which said one cap of saidelastomeric stripper engages, and said means for securing said punch tosaid punch retainer means comprises a plurality of inclined set screwsextending through the punch retainer means and into engagement with thehead portion of said punch.

6. A punch as in claim 4, wherein said punch is an elongate, solid,cylindrically shaped member having a body portion of the same diameteras the internal bore through the stripper, a reduced diameter punchpoint, and a diametrically enlarged punch head received in and securedto said punch retainer means, and wherein said means for securing thepunch to the punch retainer means comprises a ball lock means includingan inclined bore in-said punch retainer, a shallow, concave depressionin the outer surface of said punch head, and a ball in said bore andshallow depression and urged into engagement with said punch by a coilspring engaged against said ball.

7. A punch as in claim 2, wherein said stripper means comprises coilspring means, said cap means including an annular collar secured to saidpunch adjacent an upper end portion thereof and an annular workpieceengaging plate adjacent the lower end of the punch, said coil springmeans engaged between said annular collar and said annular workpieceengaging plate to urge the workpiece engaging plate downwardly relativeto said punch.

8. A punch as in claim 7, wherein an annular groove is in said punchadjacent an upper end portion thereof and a plurality of set screwsextend radially through said annular collar into engagement with saidgroove to maintain said collar and said coil spring means in positionrelative to said punch, an annular groove in said punch above saidcollar defining and axially downwardly facing shoulder, a snap ringreceived in said groove, and said annular collar engaged against anundersurface of said snap ring to transmit forces imposed on said coilspring means and collar to said snap ring and to said shoulder andpunch.

9. A punch as in claim 8, wherein a plurality of circumferentiallyspaced axial bores extend through said collar, a guide pin slidablyreceived in each of said bores in said annular collar at one end thereofand threadably engaged with said annular workpiece engaging plate at theother end thereof, and a coil spring disposed about each said guide pinand engaged at its opposite ends with the annular collar and workpieceengaging plates, respectively, said punch having a head portion abovesaid snap ring, said head portion having substantially the same diameteras said punch and secured in said punch retaining means by a ball lockDisclaimer 3,87l,254.-Lawrence V. Whistler, Jr., and Lawrence V.Whistler, III, Kenmore; and Harold J. Whistler, Williamsville, NY. MEANSFOR PIERCING AND STRIPPING THICK MATERIAL. Patent dated Mar. 18, 1975.Disclaimer filed Jan. 19, 1981, by the inventors.

Hereby enters this disclaimer to all nine claims of said patent.

[Oflicial Gazette April 7, 1981.]

1. A punch for punching holes in material, comprising: punch retainingmeans, a punch having a head end and a piercing end, punch securingmeans engaged with the head end of the punch securing the punch to thepunch retaining means, axially downwardly facing shoulder means on thepunch adjacent the head end thereof axially spaced from the punchretaining means, and resiliently yieldable stripper means disposed insubstantially coaxial relation with the punch, said stripper meansincluding a cap means secured to the punch in coaxial relation therewithin engagement with said shoulder means and axially spaced from the punchretaining means, said yieldable stripper means engaged at one endagainst said cap means and having its other end substantially coplanarwith the piercing end of the punch, so that when said punch is forcedthrough a piece of material to pierce the material the stripper meansengages between the piece of material and the cap means and thus acts asa shock absorber absorbing forces resulting from piercing the piece ofmaterial and effecting stripping of the pierced piece of material fromthe punch, with stripping loads imposed on the stripper meanstransmitted to the shoulder means on said punch to thus protect thepunch securing means supporting said punch in said punch retainingmeans.
 2. A punch for punching holes in material, comprising: a punchretainer, a punch secured at one end thereof to the punch retainer andhaving axially downwardly facing shoulder means thereon spaced from thepunch retainer, punch securing means engaged with said one end of saidpunch securing said punch to the punch retainer, resiliently yieldablestripper means disposed in substantially coaxially surrounding relationto the punch, and a cap means secured on the punch in engagement withsaid shoulder means in axially spaced relation to the punch retainer,said stripper means engaged at one end thereof against said cap meansand extended at its other end into substantially coplanar relation withthe other end of the punch, so that when a sheet of material is piercedwith the punch and the punch bursts through the material, the resultingforce imposed on the stripper means is transmitted to the shoulder meanson the punch itself, thus protecting the punch securing means from saidforce.
 3. A punch as in claim 2, wherein the stripper means comprises anelastomeric cylindrical stripper fitted over the punch and secured atits upper end to the punch adjacent the upper end of the punch.
 4. Apunch as in claim 3, wherein said elastomeric stripper is elongate andhas a central bore therethrough of substantially the same diameter asthe diameter of at least a portion of said punch, said cap meansincluding a hard rigid annular cap secured to each end of saidelastomeric stripper, one of said caps having a plurality of radiallyextending openings therethrough, and set screw means extended throughsaid openings and into engagement with said punch to secure saidstripper to said punch, the other of said caps engageable with aworkpiece to be pierced by said punch.
 5. A punch as in claim 4, whereinsaid punch is an elongate, solid, cylindrically shaped member having abody portion of the same diameter as the internal bore through thestripper, a reduced diameter punch point, and a diameterically enlargedpunch head received in and secured to said punch retainer means, and anannular, concave groove in said punch between said head and body portiondefining with said head said axially downwardly facing shoulder againstwhich said one cap of said elastomeric stripper engages, and said meansfor securing said punch to said punch retainer means comprises aplurality of inclined set screws extending through the punch retainermeans and into engagement with the head portion of said punch.
 6. Apunch as in claim 4, wherein said punch is an elongate, solid,cylindrically shaped member having a body portion of the same diameteras the internal bore through the stripper, a reduced diameter punchpoint, and a diametrically enlarged punch head received in and securedto said punch retainer means, and wherein said means for securing thepunch to the punch retainer means comprises a ball lock means includingan inclined bore in said punch retainer, a shallow, concave depressionin the outer surface of said punch head, and a ball in said bore andshallow depression and urged into engagement with said punch by a coilspring engaged against said ball.
 7. A punch as in claim 2, wherein saidstripper means comprises coil spring means, said cap means including anannular collar secured to said punch adjacent an upper end portionthereof and an annular workpiece engaging plate adjacent the lower endof the punch, said coil spring means engaged between said annular collarand said annular workpiece engaging plate to urge the workpiece engagingplate downwardly relative to said punch.
 8. A punch as in claim 7,wherein an annular groove is in said punch adjacent an upper end portionthereof and a plurality of set screws extend radially through saidannular collar into engagement with said groove to maintain said collarand said coil spring means in position relative to said punch, anannular groove in said punch above said collar defining and axiallydownwardly facing shoulder, a snap ring received in said groove, andsaid annular collar engaged against an undersurface of said snap ring totransmit forces imposed on said coil spring means and collar to saidsnap ring and to said shoulder and punch.
 9. A punch as in claim 8,wherein a plurality of circumferentially spaced axial bores extendthrough said collar, a guide pin slidably received in each of said boresin said annular collar at one end thereof aNd threadably engaged withsaid annular workpiece engaging plate at the other end thereof, and acoil spring disposed about each said guide pin and engaged at itsopposite ends with the annular collar and workpiece engaging plates,respectively, said punch having a head portion above said snap ring,said head portion having substantially the same diameter as said punchand secured in said punch retaining means by a ball lock mechanism.